1. Field of the Invention
The present invention relates to a light-emitting device emitting white light with reduced tone unevenness, which is used as, for example, an illumination light source, a light source of a backlight of a liquid crystal display, and relates to a manufacturing method thereof.
2. Description of the Related Art
In recent years, a light-emitting device has been developed which emits white light having a wide emission wavelength interval by combining a light-emitting element which emits ultraviolet light or blue light and phosphors which absorb the light from the light-emitting element and wavelength-converts the absorbed light to emit long-wavelength light. Since such a light-emitting device is used as, for example, an illumination light source, a light source of a backlight of a liquid crystal display, and the like, it is very important to reduce tone unevenness of light emitted from the light-emitting device to improve its color rendering property.
Japanese Patent Application Laid-open No. 2003-115614 discloses a light-emitting device art of forming a phosphor layer containing phosphors which are uniformly dispersed on a light-emitting element by spraying a coating solution containing the phosphors to the light-emitting element with a spray or a dispenser. This Japanese Patent Application Laid-open No. 2003-115614 realizes reduced tone unevenness since light emitted from the light-emitting element to the phosphor layer is uniformly wavelength-converted.
Japanese Patent Application Laid-open No. 2003-115614 discloses a light-emitting device art reducing tone unevenness by realizing uniform distribution of phosphors owing to a phosphor layer with a constant thickness which is formed by spraying the phosphors from above an adhesive layer absorbing irregularities of a light-emitting element and its appendix after forming the adhesive layer by applying an adhesive (epoxy resin with a thickness used as the adhesive) on the light-emitting element.
Japanese Patent Application Laid-open No. 2001-127346 discloses a light-emitting device art realizing a higher color rendering property by disposing, on a light-emitting element, a layer formed of transparent resin in which two kinds or more of phosphors performing different kinds of wavelength conversion are dispersed, and mixing light from the light-emitting element and lights wavelength-converted by the phosphors.